1 //===-- lib/comparetf2.c - Quad-precision comparisons -------------*- C -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // // This file implements the following soft-float comparison routines: 10 // 11 // __eqtf2 __getf2 __unordtf2 12 // __letf2 __gttf2 13 // __lttf2 14 // __netf2 15 // 16 // The semantics of the routines grouped in each column are identical, so there 17 // is a single implementation for each, and wrappers to provide the other names. 18 // 19 // The main routines behave as follows: 20 // 21 // __letf2(a,b) returns -1 if a < b 22 // 0 if a == b 23 // 1 if a > b 24 // 1 if either a or b is NaN 25 // 26 // __getf2(a,b) returns -1 if a < b 27 // 0 if a == b 28 // 1 if a > b 29 // -1 if either a or b is NaN 30 // 31 // __unordtf2(a,b) returns 0 if both a and b are numbers 32 // 1 if either a or b is NaN 33 // 34 // Note that __letf2( ) and __getf2( ) are identical except in their handling of 35 // NaN values. 36 // 37 //===----------------------------------------------------------------------===// 38 39 #define QUAD_PRECISION 40 #include "fp_lib.h" 41 42 #if defined(CRT_HAS_128BIT) && defined(CRT_LDBL_128BIT) 43 enum LE_RESULT { LE_LESS = -1, LE_EQUAL = 0, LE_GREATER = 1, LE_UNORDERED = 1 }; 44 45 COMPILER_RT_ABI enum LE_RESULT __letf2(fp_t a, fp_t b) { 46 47 const srep_t aInt = toRep(a); 48 const srep_t bInt = toRep(b); 49 const rep_t aAbs = aInt & absMask; 50 const rep_t bAbs = bInt & absMask; 51 52 // If either a or b is NaN, they are unordered. 53 if (aAbs > infRep || bAbs > infRep) 54 return LE_UNORDERED; 55 56 // If a and b are both zeros, they are equal. 57 if ((aAbs | bAbs) == 0) 58 return LE_EQUAL; 59 60 // If at least one of a and b is positive, we get the same result comparing 61 // a and b as signed integers as we would with a floating-point compare. 62 if ((aInt & bInt) >= 0) { 63 if (aInt < bInt) 64 return LE_LESS; 65 else if (aInt == bInt) 66 return LE_EQUAL; 67 else 68 return LE_GREATER; 69 } else { 70 // Otherwise, both are negative, so we need to flip the sense of the 71 // comparison to get the correct result. (This assumes a twos- or ones- 72 // complement integer representation; if integers are represented in a 73 // sign-magnitude representation, then this flip is incorrect). 74 if (aInt > bInt) 75 return LE_LESS; 76 else if (aInt == bInt) 77 return LE_EQUAL; 78 else 79 return LE_GREATER; 80 } 81 } 82 83 #if defined(__ELF__) 84 // Alias for libgcc compatibility 85 COMPILER_RT_ALIAS(__letf2, __cmptf2) 86 #endif 87 COMPILER_RT_ALIAS(__letf2, __eqtf2) 88 COMPILER_RT_ALIAS(__letf2, __lttf2) 89 COMPILER_RT_ALIAS(__letf2, __netf2) 90 91 enum GE_RESULT { 92 GE_LESS = -1, 93 GE_EQUAL = 0, 94 GE_GREATER = 1, 95 GE_UNORDERED = -1 // Note: different from LE_UNORDERED 96 }; 97 98 COMPILER_RT_ABI enum GE_RESULT __getf2(fp_t a, fp_t b) { 99 100 const srep_t aInt = toRep(a); 101 const srep_t bInt = toRep(b); 102 const rep_t aAbs = aInt & absMask; 103 const rep_t bAbs = bInt & absMask; 104 105 if (aAbs > infRep || bAbs > infRep) 106 return GE_UNORDERED; 107 if ((aAbs | bAbs) == 0) 108 return GE_EQUAL; 109 if ((aInt & bInt) >= 0) { 110 if (aInt < bInt) 111 return GE_LESS; 112 else if (aInt == bInt) 113 return GE_EQUAL; 114 else 115 return GE_GREATER; 116 } else { 117 if (aInt > bInt) 118 return GE_LESS; 119 else if (aInt == bInt) 120 return GE_EQUAL; 121 else 122 return GE_GREATER; 123 } 124 } 125 126 COMPILER_RT_ALIAS(__getf2, __gttf2) 127 128 COMPILER_RT_ABI int __unordtf2(fp_t a, fp_t b) { 129 const rep_t aAbs = toRep(a) & absMask; 130 const rep_t bAbs = toRep(b) & absMask; 131 return aAbs > infRep || bAbs > infRep; 132 } 133 134 #endif 135